冶金电化学对埋弧焊接过程中氧迁移的影响

对五种自制焊剂进行了正反极性的埋弧焊接,利用LECO氧分析仪测定熔滴的含氧量。结果表明：直流正接条件下熔滴的含氧量明显高于直流反接,且这一趋势随着熔渣碱度的增大而增大,间接证明了焊接电弧阴极和阳极熔渣/液态金属界面存在冶金电化学作用。进一步分析显示,在焊接参数一定的条件下,熔渣中氧离子浓度是影响熔滴阶段金属电化学增氧的关键因素。

融水苗族自治县气候与生态环境评价

利用近30a(1991—2020年)融水县气象观测数据,通过温湿指数和度假气候指数对融水县气候适宜性和度假气候进行评价,并利用融水县气象局、生态环境局、林业局等部门提供的2021年负(氧)离子浓度数据、环境空气质量监测数据、水质监测数据和林业及植被生态参量数据等,对融水县进行空气负(氧)离子状况、环境空气质量、地表水质状况、植被生态质量状况的评价。结果表明,气候舒适度为舒适等级的时段长达7个月(1—4月、10—12月),2021年的年平均负(氧)离子浓度为2689个·cm^(-3),空气优良天数占全年比重为97.5%,区域内水质达到Ⅱ类标准以上,植被覆盖度、植被净初级生产力和植被综合生态质量指数均较高。由此可见,融水县拥有得天独厚的气象生态资源,非常有利于开展负(氧)离子养生、气候康养等方面的旅游资源的开发。

影响电解液闪火电压因素的研究

研究了不同介质、pH值、导电离子电导率、杂质离子对电解液闪火电压的影响,适当的提高pH值、减少杂质离子和降低电导率等可以提高闪火电压。

Influence of silicate anions structure on desilication in silicate-bearing sodium aluminate solution

The structural changes of silicate anions in the desilication process with the addition of calcium hydrate alumino-carbonate were studied by measuring Raman spectra, infrared spectra and corresponding second derivative spectra. The results show that the desilication ratio in the solution prepared by the addition of sodium silicate(solution-SS) is much greater than that in the solution by the addition of green liquor(solution-GL), and low alumina concentration in the sodium aluminate solutions facilitates the desilication process. It is also shown that alumino-silicate anions in the solution-GL, and Q^3 polymeric silicate anions in solution-SS are predominant, respectively. In addition, increasing the concentration of silica favors respectively the formation of the alumino-silicate or the Q^3 silicate anions in the solution-GL or the solution-SS. Therefore, it can be inferred that the low desilication ratio in the silicate-bearing aluminate solution is mainly attributed to the existence of alumino-silicate anions.

Effect of chloride ion on bacterial pre-oxidation of arsenic-containing gold concentrate

The bacterial pre-oxidation process of arsenic-containing gold concentrates and the bacterial activity under different chloride ion concentrations were studied by using a mixture of thermophilic strains TCJ domesticated in production.The experimental result shows that with different samples and leaching systems,the adaptability and Cl- tolerance of bacteria are different,and that appropriate chloride ion concentration is conductive to bacterial oxidation,while higher chloride ion concentration will inhibit the bacterial activity and affect the pre-oxidation performance.Under the present production conditions,TCJ can adapt to the changes of water quality in the source of water and its critical chloride ion tolerance value is 2.7 g/L.

Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

A central composite experimental design and response surface method were used to investigate the combined effects of water temperature(18–34℃) and copper ion concentration(0.1–1.5 mg/L) on the catalase(CAT) activity in the digestive gland of C rassostrea ariakensis. The results showed that the linear effects of temperature were significant(P <0.01), the quadratic effects of temperature were significant( P <0.05), the linear effects of copper ion concentration were not significant(P >0.05), and the quadratic effects of copper ion concentration were significant(P <0.05). Additionally, the synergistic effects of temperature and copper ion concentration were not significant(P >0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

Determination of Boron Trifluoride in Boron Trifluoride Complex by Fluoride Ion Selective Electrode

A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride. The simulation indicated that the permissible aluminum masked at a certain p H value was limited and hardly related to F-concentration and boric acid. It is better to control p H value below 11.5 and the aluminum concentration within 0.025 mol/L to minimize the interference of hydroxide to the fluoride ISE. The decomposition conditions of boron trifluoride by aluminum chloride were investigated. It is found that the F-detection ratio will approach 1.0 if the Al/F molar ratio is 0.3—0.7 and aluminum concentration is no more than 0.02 mol/L when heated at 80 ℃ for 10 min. In one word, hydroxide is quite fit to mask aluminum for samples which contain high content of fluoride and aluminum and the BF3 content can be successfully determined by this method.

Physiological traits of rice seedlings in response to inorganic arsenic

The aim of our study was to better understand the different responses of rice seedling to different species of inorganic arsenic As203 （As（Ill）） and Na2HAsO4 （As（V））. Our results indicate that the biomass of rice seedling decreased as arsenic concentration increased, with the decrease being more significant at higher arsenic concentrations. In addition, the analysis of superoxide dimutase （SOD）, peroxidase （POD）, and catalase （CAT） in rice roots and leaves showed that the activity of these three enzymes significantly decreased in rice tissues, especially in rice roots, as arsenic concentration was increased,. Further, the uptake and utilization efficiencies of N, P, and K were found to decrease as arsenic concentration was increased. However, the uptake and utilization efficiencies of P and K were mainly affected by As（IlI）, whereas those of N were mainly affected by As（V）. Inductively coupled plasma-mass spectrometry （ICP-MS） was used to assay arsenic accumulation in rice tissues; the results indicate that the arsenic content in rice tissues was enhanced when arsenic concentration was increased, especially in rice roots after arsenic treatment.

Resolving the hydrothermal signature by sequential leaching studies of sediments from the middle of the Okinawa Trough

A sediment core H9 collected from the middle of the Okinawa Trough was studied by sequential leaching to indentify the hy- drothermal component from the various other components such as detrital, biogenic, and so on. The elements were partitioned into five fractions： exchangeable, bound to carbonates, bound to iron and manganese oxides, bound to organic matter, and re- sidual. The contents of elements A1, Ti, K, Fe, Mn, Pb, Co, Cu, Ni, and V in each fraction were determined and their percent- ages were calculated. Residual fraction is a dominant speciation for most studied elements except for Mn and Pb in the core sediments. For the elements A1, Ti, and K, residual fraction accounts for more than 95% of the total metal concentration. The concentrations of all studied elements in the exchangeable fraction, carbonate fraction, and organic fraction are relatively low. The metal levels in the iron and manganese oxide fraction are relatively high and this fraction represents another prevalent speciation. Also in this fraction, the metal concentrations and percentages are higher in the core section above 80 cm than those below 80 cm. Especially for Mn and Pb, the fractions bound to iron and manganese oxides account for more than 50% of the total metal concentration for the upper 80 cm section. Hydrothermal components mainly occur in this fraction. And the downcore variations of metal contents and percentages reflect the variations of hydrothermal inputs to the sediments. The high metal levels in the upper core indicate the enhancing influence of hydrothermal activities around on the core H9 during its late stage of sedimentation. The accumulation rates of hydrothermally derived Fe, Mn, Pb, Co, Cu, Ni, and V were evaluated based on their concentrations in the iron and manganese oxide fractions in this study. The results show that the accumulation rate of hydrothermally derived Mn is similar to those obtained from the Mid-ocean Ridges and Lau Basin. However, hydrothermally derived Fe and Cu present a relatively lower level.